Margo can purchase tile at a store for $0.89 per tile and rent a tile saw for $45. At another store she can borrow the tile saw for free if she buys tiles there for $1.39 per tile. How many tiles must she buy for the cost to be the same at both stores?

Margo must buy tiles for the cost to be the same at both stores.

She must buy 90 tiles for the cost to be the same at both stores

Step-by-step explanation:

Let x be the no. of tiles bought for the cost to be the same at both stores

Margo can purchase tile at a store for $0.89 per tile at shop 1

Cost of x tiles =0.89x

She rent a tile saw for $45.

So, total cost at Store 1 = 0.89x+45

At another store she can borrow the tile saw for free if she buys tiles there for $1.39 per tile.

So, cost of 1 tile = 1.39

Cost of x tiles = 1.39x

ATQ

0.89x+45=1.39x

45=1.39x-0.89x

45=0.5x

90=x

Hence She must buy 90 tiles for the cost to be the same at both stores